Sankaracarya's Vivekachudamani 430

यस्य स्थिता भवेत्प्रज्ञा यस्यानन्दो निरन्तरः ।

प्रपञ्चो विस्मृतप्रायः स जीवन्मुक्त इष्यते ॥

yasya sthitā bhavetprajñā yasyānando nirantaraḥ |

prapañco vismṛtaprāyaḥ sa jīvanmukta iṣyate ||

(Sankaracarya's Vivekachudamani 430)

One who has steady wisdom, who experiences endless Bliss, who has forgotten the phenomenal world, that person is considered a jivan-mukta, one-liberated-while-living.

A liberated soul doesn't mean one has to leave his material body and go to the Spiritual world, A person who attains bliss by getting Vedic knowledge and get rid of material attachment can still be liberated while he is living in this world. Such people are very rare. All of us must try to get a higher position. For example, how everyone trying to get higher material education ye not everyone can be successful but without trying no one can be successful. Therefore one has tried to get Jivan-mukta or liberation even in this material body that is the higher perfection of life.